Anonymous Posted on Sep 27, 2012

'81' GS550L Breaks Up Over 5000 RPM, Blows Black Smoke, Runs Normal Up To That Point, Valve & Ign. Timing Right, Good Compression, Float Height, OK

Installed A Dynatec Ign. (Which Dynatec Assured Me Was OK To Use), Checked Valve Clearance, Synchronized Carbs. New Plugs, Whats Left?

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Anonymous Oct 05, 2012

Some ##*%!!*^#$*$# Never Put The Rubber Plugs That Go In The Idle jet Orfice, A So Called Repair Shop Worked On This First, I Really Questioned Myself Untill I Found This !
Anonymous Oct 05, 2012

Runs Great Now ! Runs Great Now !
Bobby Blevins May 17, 2014

Awesome! Glad you found it ! Awesome! Glad you found it !

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John Dub

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Posted on Apr 30, 2014

John Dub

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Carbs was 26 mm

Bobby Blevins

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Posted on Sep 29, 2012

Bobby Blevins

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It could be jetted too rich,the choke could be engaging at WOT,or,you could most likely have weak valve springs which are "floating" the valves at higher RPM's.Also,you might try lowering the needles in the carbs by a couple clicks.
Good Luck!

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Anonymous

6966 Answers
Posted on Apr 27, 2009

SOURCE: 1979 suski 750,bike runs on 2 left side cylinders,

Hi and welcome to FixYa,

With the indulgence of craigjamesbt...

A few additional ideas to consider:

it would be an electrical/ignition issue if 1 & 4 or 2 & 3 will not fire but not 3 & 4;
almost always, raw fuel on exhaust indicates a flooded engine. A flooded engine would most likely be a carb issue;
best way to determine if it is an engine concern is to do a compression test;
a way to test the right carb pair is to deliberately starve them of fuel by temporarily plugging/blocking the inlet port/seat with rubber similar in appearance as to those used for glue gun, not installing the needle and float. Assemble the carb and install. Start the bike and use/spray carb cleaner on the right side carb. Note if 3 & 4 will fire even intermittently.

Would appreciate a postback on results/updates on any developments.

Good luck and thank you for using FixYa.

mike

112 Answers
Posted on Jun 28, 2009

SOURCE: rpm problem

check that your air filter and intake tubes are clear

Anonymous

11896 Answers
Posted on Aug 17, 2009

SOURCE: Wont idle ,motor tapping below 1300 rpm

Carbs need to be removed, dismantled and cleaned. Soak in solvent or equivelant for a couple hours and use air nozzle to blow dry. Make sure to blow out jets.

Anonymous

267 Answers
Posted on May 08, 2010

SOURCE: floats not set

Float tabs come set flat to surrounding plate, bend up to decrease level and down to raise level. Raised level too much and you risk fuel overflow on sustained inclines and too low a level and you will lean out at high revs and damage valves/piston real quick. There is no set level to speak of, but better to err on the side of losing a bit of overflow. The overflow drains from the carby via a plastic hose from just above float bowl flange.
Cheers.

kiaikid

7 Answers
Posted on Sep 21, 2010

SOURCE: Float height Adjustment 85 GS550L Suzuki

22.4 mm + or - 1.0 mm.
http://members.dslextreme.com/users/bikecliff/images/carbspec_float_height.html#A05

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1981 Gs 550 L

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'81' GS550L Breaks Up Over 5000 RPM, Blows Black Smoke, Runs Normal Up To That Point, Valve & Ign. Timing Right, Good Compression, Float Height, OK